Analysis of vibrational temperature of patterns in two-gas-species discharge by using photoelectronic detection systems

Abstract

The non-intrusive optical emission spectroscopy of the N₂ second positive band system (C³Π_u→B³Π_g) are used to measure the vibrational temperature in N₂/Ar and air/Ar discharges at atmospheric pressure, respectively. In N₂/Ar discharges, the strip patterns can be obtained at the concentration of N₂ from 9.5% to 38% at 10kV and 60kHz, and its vibrational temperature increases approximately from 1600K to 1750K with increasing the N₂ concentration. Increasing the concentration of N₂ from 38% to 96%, the hexagon patterns are formed and its vibrational temperature increases from 1750K to 1950K. In air/Ar discharges, three patterns (strips, quasisuperlattice and hexagon) are obtained with air concentration increasing from 9.5% to 96% at 10kV and 60kHz. The vibrational temperature ranges approximately from 1850K to 2750K, which is about 250~600K higher than that in N₂/Ar discharges under the same concentration of N₂ and air in two-gas-species. In addition, the quasisuperlattice can be observed at the air concentration from 19% to38%, and its vibrational temperature is from 2000K to 2300K approximately. It indicates that the gas species and the mixing ratios affect the patterns and their vibrational temperatures. Furthermore, it is also found that the breakdown voltage and the moment of discharge initiation are different as a function of the gas species and the mixing ratios.